A back-illuminated image sensor chip comprises a semiconductor layer, one face of which, referred to as the front face, is covered with an interconnection structure, and the face of which that is opposite the front face, referred to as the back face, is intended to receive illumination. The chip comprises a matrix of pixels, formed in and on the semiconductor layer, elements of which, such as transistors, are formed on the side of the front face and are connected to each other via the interconnection structure.
A chip of this kind is manufactured from a semiconductor die or layer. In practice, a plurality of identical chips are formed simultaneously in this die, which is then sliced in order to obtain individual chips. Before slicing, a handle or carrier is bonded to the side of the interconnection structures formed on the front face of the semiconductor die, and then the die is thinned from its back face. After thinning of the semiconductor die, for each chip, conductive connecting vias are formed through the handle, as far as portions of the upper level of metallizations of the interconnection structure of this chip. The semiconductor die provided with the handle is then sliced in order to obtain individualized chips.
In a chip manufactured in the manner described above, after the step of slicing or sawing, delaminations may be observed at the bonding interface of the handle on the interconnection structure. These delaminations extend from the edges of the chip and may propagate over a large part of the bonding interface. This may result in malfunctioning of the chip, in particular on account of rupturing of one or more conductive connecting vias.
There is a need in the art for a back-illuminated image sensor chip comprising means for preventing the propagation of delaminations at the bonding interface of the handle on the interconnection structure. It would also be desirable to have a method for manufacturing a chip of this kind that comprises few or no additional steps with respect to a conventional manufacturing method.